Cancel intermediate builds

Author: avik-pal

.github/workflows/CI.yml

@@ -6,6 +6,11 @@ on:
   push:
     branches:
       - master
+concurrency:
+  # Skip intermediate builds: always.
+  # Cancel intermediate builds: only if it is a pull request build.
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
 jobs:
   test:
     runs-on: ubuntu-latest

.github/workflows/Downstream.yml

@@ -4,7 +4,11 @@ on:
     branches: [master]
     tags: [v*]
   pull_request:
-
+concurrency:
+  # Skip intermediate builds: always.
+  # Cancel intermediate builds: only if it is a pull request build.
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
 jobs:
   test:
     name: ${{ matrix.package.repo }}/${{ matrix.package.group }}/${{ matrix.julia-version }}